roundiv – Division of integers with rounding

Write a program that computes the rounded integer division between two integers, i.e. divide and round to the nearest integer. For the purposes of this exercise, this should be done without resorting to floats or doubles. Halfway cases, where the fractional part is exactly “.5”, should be rounded to the nearest even integer. Here are a few examples:

the nearest integer to 4 divided by 3 is 1;
the nearest integer to 8 divided by 3 is 3;
the nearest integer to 100 divided by 80 is 1;
the nearest even integer to 18 divided by 12 is 2.

Rounded division of integers

Input and Output

Each line of input will contain two integers n and d in the range:

-2 000 000 000 ≤ m, n ≤ 2 000 000 000

For each line of input your program should produce a line of output with the result of rounding m divided by n.

Example input

Example output

The `roundiv` function

Your program should be implemented using an roundiv function that receives two integers as arguments and returns an integer. Please refer to the information for the chosen language:

C prototype: int roundiv(int n, int d);
Python definition: def roundiv(n,d):
Haskell type: roundiv :: Int -> Int -> Int
C++ prototype: int roundiv(int n, int d);
C# definition: public static int Roundiv(int n, int d) in a public class Program
Java definition: public static int roundiv(int n, int d) in a public class Roundiv
JavaScript definition: function roundiv(n,d)
Lua definition: function roundiv (n, d)
Ruby definition: def roundiv(n,d)

For the purposes of this exercise, you should not use floats or doubles when implementing roundiv nor rounding functions provided by your language of choice. The point here is to exercise the implementation of rounding.

Scoring

Submit your solution to be graded according to the following list:

1/12: works for the above example but produces output in an incorrect format
2/12: works for the above example and produces output in the correct format
3/12: divides multiples and divisors correctly
4/12: rounds down in the correct cases
5/12: rounds up in the correct cases
6/12: rounds halfway cases correctly
7/12: divides negative numbers
8/12: divides large integers
12/12: implements the roundiv function

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